Soccer star Cristiano Ronaldo has denied reports of an affair with a Brazilian model, insisting that her explosive claims are "pure fiction."

On Sunday Andressa Urach spoke out publicly about an alleged tryst that she says occurred April 22 with the Real Madrid striker. She claims they began chatting via text and social networking site Skype before their alleged recent night out.

Ronaldo, who has been dating Sports Illustrated model Irina Shayk since 2010, wasted no time denying Urach's cheating claims. She gave The Sun a detailed description of her alleged night with the Portuguese athlete.

"I was informed that The Sun, faithful to its editorial line, will publish an article where is given voice to a so called Andressa - someone seeking the limelight on my account. And I wonder why this happens one day before a very important game for my team. Deeply outraged by a situation intended, in vain, to affect my personal life," Ronaldo wrote via his personal Twitter account.

"I just want to clarify I was in fact at the Hotel Villa Magna on April 22 giving an interview to Manu Sainz, something the reporter himself is able to corroborate. Everything else is pure fiction and forgery," he added.

Urach, 27, also claims that Ronaldo, who has one child with an American woman, told her he "wasn't serious" about his relationship with Shayk, 27.

"Cristiano told me to come to Madrid and that we'd meet, but he would not tell me where or when exactly. He said he had to be careful because if it came out that he'd seen me, his girlfriend wouldn't be happy," she said.

"They are together, but he told me the relationship wasn't serious. He didn't say anything else about her," she added.